Gears: Lift It Up!

It is easy to visualize how a gear ratio can speed things up. A difficult concept to grasp without seeing an application is how the torque is affected by a gear ratio. In this activity, students learn of the trade-off between speed and torque when dealing with gear ratios. A LEGO pulley system with two independent gear sets and motors spin two pulleys. Wrapped around the pulleys are strings to which weights are attached. The effect of adding more and more weight to the pulley systems with different gear ratios is observed as the system’s ability to lift the weights is tested.